If the FDA can stick to its self-imposed deadlines, a flurry of activity scheduled at the agency in the next couple of days will dramatically affect some drugmakers' futures. While FDA approval decisions are tough to handicap, they can produce exciting and scary stock-price movements. Let's look at some of the more interesting FDA actions next week.

CV Therapeutics (NASDAQ:CVTX)
CVT's lead drug Ranexa has been approved since early 2006 to treat angina in patients who don't successfully respond to other treatments. Despite being one of the first new angina treatments to come onto the market in years, and despite angina affecting millions of patients, Ranexa's restrictive label has hampered its sales. The drug pulled in just $22 million in the first quarter.

All this could change for Ranexa in the coming weeks, though. CVT has three potential Ranexa label-expanding marketing applications awaiting FDA review, with July 27 PDUFA dates.Three separate FDA marketing applications could expand Ranexa's use into frontline angina and diabetes for coronary artery disease patients, and add anti-arrhythmic efficacy claims onto its label.

Ranexa has excellent odds of gaining frontline angina approval; CVT inked what is known as a Special Protocol Assessment (SPA) with the FDA, then ran a clinical study that met the FDA's requirements for it. An SPA is a formal agreement that theoretically helps to lock the agency into a set of requirements for a drug's approval. If a drug can clear those hurdles in clinical testing, it'll usually get a thumbs-up at the agency.

The other two Ranexa marketing applications, for diabetes and arrhythmias, are more in doubt. A recent advisory panel hearing on updating the guidelines for the approval of new diabetes treatments concluded that the requirements for such drugs should be tightened. Since the FDA is still likely digesting this panel's recommendations, it could mean near-term delays on Ranexa and any other drugs awaiting FDA review for diabetes.

As for arrhythmia, Ranexa's chances are more unknown. There's precious little information available to handicap the FDA's opinion on this application. Of the three Ranexa marketing applications, though, this one's probably the least important. Approval for the improved angina label or diabetes claims would be much larger wins for the Rule Breakers pick, significantly broadening Ranexa's label within existing or new patient populations.

Shares of CVT look undervalued, considering Ranexa's risk-adjusted potential. Despite the strong likelihood that the FDA could arbitrarily delay its review of the Ranexa marketing applications, the market isn't betting as strongly against CVT as it is some other drugmakers with impending PDUFA dates.

Vanda Pharmaceuticals (NASDAQ:VNDA)
Vanda also has a July 27 PDUFA date set for a New Drug Application with the FDA, awaiting a decision on its atypical antipsychotic schizophrenia drug candidate Fiapta (iloperidone).

The market opportunity for new types of these treatments is in the billions of dollars. With a market capitalization of only $100 million, Vanda clearly has multibagger written all over it, provided it can get Fiapta marketing approval even with a restricted label.

Unfortunately for Vanda, that atypical antipsychotic drug market is also incredibly crowded, with compounds like Eli Lilly's (NYSE:LLY) Zyprexa, Pfizer's (NYSE:PFE) Geodon, and Bristol-Myers Squibb's (NYSE:BMY) Abilify among many such drugs already approved to treat schizophrenia. Given the current regulatory climate at the FDA, and no urgent need for another antipsychotic on the market (aside from longer-acting therapies), Fiapta's odds of getting approved look tough.

If Fiapta does win approval, it would probably be the biggest surprise regulatory decision of the year for me (and many others, judging by the short interest in Vanda shares). Anything is always possible at the FDA, and Vanda's share price is definitely reflecting low expectations for Fiapta. Still, there's room for Vanda to fall further -- Fiapta could always receive an approvable letter that can only be rectified with onerous, long-term clinical trial requirements.

Roche (OTC: RHHBY.pk)
You won't find a lot of U.S. investors holding shares of biotech giant and lead Genentech shareholder Roche -- it's only listed on the Pink Sheets out here. Nonetheless, Roche does have an FDA advisory panel meeting next week that should matter to many large-cap biotech and pharma investors.

On Tuesday, July 29, an FDA advisory panel will decide whether to recommend approval of Roche's humanized IL-6 inhibitor Actemra to treat rheumatoid arthritis. This novel-acting biologic could have blockbuster written all over it, if the advisory panel hearing and eventual FDA ruling both go in its favor.

Actually, "blockbuster" might be an understatement. Numerous other biologics that help with rheumatoid arthritis and other inflammatory conditions, like the TNF inhibitors from Amgen (NASDAQ:AMGN) (Enbrel), Abbott Labs (Humira), and Johnson and Johnson (NYSE:JNJ) (Remicade), have become biotech's biggest success stories over the past several years.

Actemra is already approved in Japan. With its differentiated mechanism of action, Actemra's U.S. approval could shake up the rheumatoid arthritis market, if next week's advisory panel hearing goes well.

Perhaps this article should be delayed three months
The FDA's been consistent about at least one thing this year: The arbitrary several-week-long (or longer) delays it's imposed in reviewing many drug marketing applications. Just this week, Amgen's blood disorder compound Nplate had its approval decision delayed indefinitely for some untold FDA reason. There's always a chance it'll keep us waiting on these drugs, too -- but if it doesn't, next week's decisions could lead to serious fireworks, or equally dramatic meltdowns.

CV Therapeutics has underperformed in our Rule Breakers portfolio since being selected in 2005. That hasn't stopped the rest of the Rule Breakers recommendations from beating the market, though. Check out all our other picks with a 30-day free trial.

Pfizer is an active Inside Value pick. Pfizer, Eli Lilly, and Johnson and Johnson are active Income Investor picks.

Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has an A+ disclosure policy.